Elijah was analyzing the trajectory made after throwing a football. His coach was able to measure that his throw reached a maximum height of 16 feet after 2 seconds. He figured that the ball left his hand at a height of 4 feet. Let the independent variable represent time and the dependent variable represent height of the ball. Use this information to write an equation to model the path of the ball and predict when the ball will hit the ground.
The ball will hit the ground at approximately__ seconds. Round to the nearest tenth.